Nonoverfill device



March 10, 1942. HILL 2,275,526

NON-OVERFILL DEVICE Filed May 17, 1939 40/7 IN EN TR;

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"Pienid Ms. 10,1942

NONOVERFRL DEVICE Robert H. Hill, Anderson, Ind, asslgnor to General Motors Corporation, Detroit, Mich, a corporation. of Delaware Application May 17, 1939, Serial No. 274.15%

3 Claims. (ill. ltd-lit) This application is a continuation in part of my copending application Serial No. 264,385, for Storage battery filed March 30, 1939, and relates to'nonmverrlll devices for storage batteries and is poured into the cell. The skirt extends from the cover top-wall to substantially the desired level of the electrolyte. In order to vent the battery while in use,'the cover provides a by-pass for connecting the space exterior to the skirt (and in which air may be trapped) with the space within the confines of the skirt. The by-pass is controlled by a valve, which is automatically closed when the filler hole plug is removed from the cover and is opened when the plug is screwed in place, so that the venting-of the air-trapping space may take place through the by-pass,

through the space within the skirt and out through a hole provided by the plug. In order, that the valve will close automatically when the plug is removed, it is necessary to provide means which will urge the valve against its seat and which will yield when the valve is pushed away from its seat by screwing the tiller hole plug in It'is an object of the present invention to provide a resilient valve closing means which will not be corroded by the electrolyte of the battery. According to the present invention, I have accomplished this object by the use of a helical coil spring of acid resisting material such as glass and preferably Pyrex glass.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a sectional view of abattery cell' cover showing the vent valve held in closed position by a helical spring of acid resisting material, the

p filler plug or cap being removed as shown in Fig.

Fig. 2 is a. view similar to Fig. 1 showing the filler plug screwed into position and the vent valve open.

Fig. 3 is a perspective view showing principally the under side or the. vent valve.

Fig. 4 is a perspective view showingprincipally the upper side of a vC-shaped resilient hard rubher snap ring for retaining the vent valve spring.

Fig. 5 is a top plan view of the vent valve.

Fig. 6 is the sectional view taken on the line and looking in the direction of arrows tt of Fig. 1.

Fig. 7 is a view similar to Fig. 2 showing a modified form of vent valve spring.

Reierrlng to Fig. 1, battery cell cover 2i! includes a top wall 2i and side walls 23 having flanges 23 adapted to be supported on ledges provided by the side walls of the battery cell, not

' shown. It will be understood that the cell con- 'or'cap 26 provided with a vent29.

The cover is provided. with a byspass 33 connecting the space exterior to the skirt 24 with the space within the skirt 24. This by-pass is controlled by a valve 3| made of hard rubber or other acid resisting material. When the cap 25 is removed, as shown'at Fig. 1A, the valve 3! is urged upwardly on its seat 32 by a helical coil spring 40 of acid resisting material such as Pyrex glass. As shown in Fig. 6, the seat 32 is one of three pads 32, 33 and 34, which provide a three point bearing for the valve 3|.

The spring 40 is confined between the valve 3| and -a hard rubber C-washer 35 which is sumciently resilient to be compressed and pushed to provide for the venting 01 the space above the electrolyte level and exterior to the skirt 24. The venting is provided by the by-pass 30 which is in communication with the space within the skirt 24 which is open to the outside air through the notches 38 between the boss segments 31 oithe valve 3| and through the vent hole 29 of cap 28..

when the cap 28 is removed as shown in Fig. 1A to permit the pouring of. liquid into the cell 2. age-mace a through the filler-hole 25 in cover 20, the vent valve ii is caused to move upwardly by expansion' of spring 40, thereby closing the by-p'ass 30 so that air will be trapped inthe space between the exterlor of the skirt 2! and the side wall of cover 20 and the battery cell. As the liquid is poured into the cell, its level will rise to that of the lower edge of the skirt :4 and thereafter. air will. be trapped in the space mentioned whereupon the additional liquid will flll the in-' terior of skirt 24 without-causing appreciable rise of the electrolyte in the region exterior to the skirt. The sudden rise of liquid within the skirt indicates that the electrolyte has been brought up to the desired leveland that further addition of liquid would result in the liquid overflowing the cover; however, the battery cell willnot be overfllled.

above the electrolyte and within the confines of the battery cell and cover. In this connection, it will'be understood that the cover is oblong in contour and that the sectional views shown in Figs. 1 and 2 are taken across the shorter V dimension of the cover. 1

In the manufacture of helical springs of glass it.is easier-to make the \spring of uniform cross section throughout as the spring is made by winding a round bar of glass, while heated to the plastic state, around a mandrel. .This process produces a spring of uniform section throughout as shown in section in Figs. l and .2. In order that such'a spring can be used most eil'ectively, the under side of E the valve 3| can be provided with an annular boss II A, the upper surface of a portion of which is helicallywinclined at least from the shoulder MB to the line diametrically opposite 3|C. Similarly the upper side of the c-washer 35 is provided with an annular boss 35A, the upper surface of which is partly helically inclined as from the shoulder of line 353 to the line 350. In this way substantial portions of the end turns of the spring are in engagement with the valve 3i and the washer 35.

The helical glass spring 40A shown in Fig. 'I is one in which the end turn material has been tapered so that the ends ofthe spring'will be substantially flat and perpendicular to the axis thereof, thus conforming in shape to that of a conventional steel spring having its ends ground off. The spring 40A is more expensive than the spring 40 on account of the additional steps required to reduce or taper the material of the end turns. These steps 'must be taken while the glass is plastic as it is not commercially practical to grind oil the end turnsto make them flat as in the case of a metal spring. If springs like lllAare available, then the bosses 3IA of valve 3| and 15A of washer 35 can be omitted. However, it is believed that the simplification of the parts 3! and 35 by omitting the bosses "A and 35A would not compensate for the additional cost of the spring "A. Therefore, the'construction shown in Figs. 1 and 2 is preferred on account of cost. 7

While the embodiment of the present invention as herein disclosed, constitutes a preferred form,

it-is to be understood that other forms might be adopted, all coming within the scope of the claims which follow. What is claimed is as follows:

-1. A cell cover construction for storage battery containers comprising a cover having. a filler opening and a skirt providing a space communicating with thefiller opening, said skirt extending from the top wall of the cover to such distance that, when the cover is assembled with the battery container, the lower edge of the skirt will be at the proper level of the electrolyte within the container, said cover providing a bypass passage connectlng the space surrounding the exterior of the skirt with the space within.

the skirt and filler opening, a'valve of acid resisting material having an aperture communicatingwith the filler opening located in the space within the skirt and engageable with a seat provided by the cover in order to close the by -pass, a

vented plug for closing the filler opening and for engaging the valve to move it from its seat when the plug is assembled with the cover, and a helical spring of glass located in the space within th skirt and supported thereby for urging the valve toward its seat.

'2. A cell cover construction according to claim 1 in which the spring is uniformin crosssectlon throughout its length, in which the skirt. is provided internally near its lower edge, with an annular groove which receives a resilient C-washer or split ring of acid resisting material which supports the spring, and in which the valve and the c-washer are provided with spring contacting surfaces so shaped that the valve and 'c-washer engage substantial portions of the end turns of the spring.

3. In a storage battery, a cover having a filler opening and a skirt depending a predetermined distance below the underside of the'cover and providing a continuation of the filler opening, said cover providing a seat within the skirt, said cover also being provided with a by-pass having one end terminating in the spaceexterior of the skirt and under the cover and the other end ter minating at the seat, a hard acid resisting ring located within the skirt and adjacent the seat; a c-washer of hard acid resisting insulating the seat and compress the glass spring, said .spring urging the ring against the seat to seal the by-pass when the plug is removed from the cover. 7

ROBERT H. HILL. 

